In a number of environments, a bus may comprise a number of lines connecting electronics equipment. The number of lines may carry signals in one direction or in two directions depending on the configuration of a communication system employing the lines. Design limitations of the communication system may result in only a portion of the communication capacity of the bus being utilized.
An example of a particular environment is a communication environment. An example of a particular bus within a communication environment is an aviation bus defined by the ARINC 429 specification. The ARINC 429 specification defines the physical and electrical interfaces of a bus for a communication system in an aircraft. The bus connects up to thirty one different pieces of electronics equipment in an aircraft to a data acquisition unit. Specifically, the ARINC 429 bus is a twisted shielded wire pair with connectivity known as the Mark 33 Digital Information Transfer System (DITS). Signals carrying data are sent in one direction on one wire to the data acquisition unit. Other signals are received from the data acquisition unit traveling in the opposite direction on the other wire.
The twisted shielded wire pair in the ARINC 429 specification and the Mark 33 Digital Information Transfer System provides high reliability and high resistance to interference. The high reliability and the high resistance to interference come at a cost. The cost includes wire weight and limited data rates. Furthermore, the ARINC 429 specification provides a bus that is unidirectional for transmission on one line and unidirectional for reception on another line. In addition, the ARINC 429 bus is currently limited to thirty one pieces of equipment and one data acquisition unit.
Accordingly, it would be advantageous to have a method and apparatus which takes into account one or more of the issues discussed above, as well as possibly other issues.